The invention relates to a percutaneous implant, especially neurological apparatus comprising a percutaneous access device suitable for use with an implanted intracranial catheter.
A percutaneous device is a device which crosses the skin, providing a connection between the interior and exterior of the body. Such devices include dental implants, external hearing aid attachments, artificial limb attachments and semi-permanent catheters. Some percutaneous devices are anchored into bone and some are anchored in soft tissue. All percutaneous devices protrude out of the skin, breaking the barrier that the skin usually provides against infection. Percutaneous devices fail due to a number of reasons, including marsupialisation, in which the epithelium grows down and forms a pocket around the device thereby rejecting the device. More seriously, though, a percutaneous device is a potential site for infection. Accordingly, it is vital that the junction between the skin and the device is able to prevent infection.
The delivery of therapeutic agents to a particular site in the body can pose a number of problems. For example, a patient may have to undergo repeated surgery to access a site to which a therapeutic agent is to be delivered. It is possible in certain areas of the body, such as the brain, to implant a catheter, allowing permanent access to a specific site. Nevertheless, at present, such catheters do not protrude through the skin, and a patient still requires surgery to expose the end of the catheter and administer therapy. It would be particularly desirable to provide a percutaneous port that can be connected to an implanted catheter to allow repeated delivery of a therapeutic agent. As mentioned above, such catheters may be placed in the brain. Delivering therapeutic agents to the nervous system presents a significant challenge.
Delivery via the bloodstream in most cases is extremely limited due to the inability of some therapeutic agents to cross the blood-brain barrier. An alternative approach is to bypass the bloodstream and introduce agents directly into the nervous system via a catheter system. Such catheterisation is a delicate procedure and for any treatment regime that requires intermittent delivery of therapeutic agents over a period of time it is desirable to leave the catheter in place between sessions. It would be of a significant advantage to provide a percutaneous port that would allow repeated access to a permanent or semi-permanent catheter, without the patient having to undergo surgery. If such a port were provided, it would be critical to prevent bacterial ingress into the catheter and hence into the central nervous system (CNS). Prevention of infection via the port and via the junction between the port and the body would be vital to the patient's safety.
Percutaneous devices have been described in the prior art, however, the described devices are generally for use for accessing a patient's blood stream, rather than the CNS. Examples of such devices for accessing a patient's blood stream are described in US2004/0249361, U.S. Pat. No. 6,607,504 and U.S. Pat. No. 5,098,397.